The present invention relates to an electrically controlled broadband group antenna comprising a plurality of antenna elements arranged in a common plane Hand connected to a feeder unit. The invention also relates to an antenna element suitable for incorporation in an electrically controlled broadband group antenna, the antenna element comprising a rotationally-symmetrical body tapering towards one end. In addition, the invention relates to an antenna module with a plurality of such antenna elements. These group antennas preferably work with linear polarization or two orthogonal polarizations.
Electrically controlled broadband group antennas with an instantaneous bandwidth larger than one octave are a very important component in, among other things, military telecommunication systems and multifunction radar. There are currently only a few broadband antenna elements that are suitable for electrically controlled broadband group antennas. These antenna elements have a plurality of disadvantages.
A known type of broadband group antenna uses antenna elements that have the name “Tapered Slot”. See, in connection with this, IEEE Transactions on Antennas and Propagation, volume 48, no. 11, November 2000, pages 1707-1718, Experimental Results of 144-Element Dual-polarized Endfire Tapered-Slot Phased Arrays. In general, for known electrically controlled broadband group antennas, it is the case that the antenna elements are complicated and their production is difficult and therefore expensive. This applies in particular for group antennas with two orthogonal polarizations. In addition, it is often difficult to connect the antenna elements to an underlying microwave unit.
With regard to group antennas with “Tapered Slot” antenna elements, we can mention in particular difficulties in achieving electrical contact between adjacent antenna elements, which is important for the electrical function. This applies, in particular, for high frequencies, as the element distance is small. For example, the element distance is only approximately 8.5 mm at a frequency of 18 GHz. Another difficulty is in connecting the antenna elements to an underlying lobe-shaping network or to underlying microwave units. In addition, there is the danger that electromagnetic resonances will arise in the antenna elements. These resonances can considerably impair the electrical characteristics of the antenna elements.